1. Field of the Invention
The present invention relates to a switch device suitable for use in, for example, a driving switch of a vehicle-mounted power window apparatus, which is capable of selectively operating two sets of switch elements by rockably operating an operating knob.
2. Description of the Related Art
Conventionally, as a driving switch of a vehicle-mounted power switch, a driving switch is proposed in which two sets of slide-type switch elements are juxtaposed to each other and an operating rod of an operating knob is rockably operated to turn on the respective switch elements (for example, see Japanese Examined Patent Application Publication No. 5-80770).
FIG. 11 is an explanatory view illustrating a conventional example of such a driving switch. In this drawing, the switch unit 1 generally has a structure in which two sets of slider-type switch elements are disposed within the case (not shown) whose upper opening is covered with a cover member 2. Driving shafts 3 and 4 of the respective switch elements protrude outward from elongated holes 2a and 2b of the cover member 2. The two sets of switch elements are disposed in the case in a straight line that coincides with the sliding direction (right-and-left direction in the drawing) of the driving shafts 3 and 4. Terminals 5 of a plurality of fixed contact pieces are exposed into the case and protrude downward from the case. Although not shown, each of the switch elements is provided with a slider having the driving shaft 3 (or 4) protruding therefrom, movable contact pieces that are fixed to the slider and brought into contact with or separated from the fixed contact pieces during operation, a coil spring that normally biases the slider toward an initial position illustrated in FIG. 11, and a plate spring that is brought into resilient contact with the slider and normally biasing the movable contact pieces toward the fixed contact pieces.
The above-mentioned conventional switch unit 1 is assembled into a housing 6. An operating knob 7 is disposed in a mounting recess 6a of the housing 6. The operating knob 7 can swing about a spindle 8, and operating rod 9 moves (tilts) in the direction of the arrow “A” or “B” along with the swinging of the operating rod 7. Also, the tip of the operating rod 9 is inserted between the driving shafts 3 and 4 of the two sets of switch elements. Thus, when an operator pushes in the operating knob 7 to move the operating rod 9 in the direction of the arrow “A”, the operating rod 9 causes the driving shaft 3 to be pushed in and slid in the left direction in the drawing against the biasing force of the coil spring. As a result, the movable contact pieces, which integrally slide with the driving shaft 3, are brought into contact with or separated from the corresponding fixed contact pieces, such that one switch element is switched from its OFF state to its ON state. In this state, when a pushing force applied to the operating knob 7 is removed, the coil spring, which has been compressed by the sliding of the driving shaft 3, biases the slider to cause the driving shaft 3 to be slid in the opposite direction. Therefore, the switch element is automatically returned to its OFF state in FIG. 11. The operation of the switch element when an operator pulls up the operating knob 7 to move the operating rod 9 in the direction of the arrow “B” is basically the same as the above-mentioned operation. Here, when the operating rod 9 pushes in the driving shaft 4 in the right direction in the drawing to allow the sliding of the driving shaft 4, the other switch element is switched from its OFF state to its ON state. When operating force applied to the operating knob 7 is removed, the switch element is automatically returned to its OFF state.
In the above-mentioned conventional example, the driving shafts 3 and 4 slides in a straight line. However, the operating rod 9 that pushes in the driving shafts 3 and 4 are members swinging about the spindle 8. Thus, the driving shafts 3 and 4 are pushed in a direction upwardly inclined with respect to the sliding direction. In addition, during operation, the driving shafts 3 and 4 are pressed against the peripheral walls of the elongated holes 2a and 2b, or the slider is pressed against the inner wall of the case 2 while being inclined. This may increase sliding resistance partially and undesirably and result in the sense of irregularity or saccade. Therefore, a problem occurs in that a good sense of operational touch is rarely obtained. Meanwhile, if the operating rod 9 is made long to arrange the spindle 8 away from the driving shafts 3 and 4, the driving shafts 3 and 4 can be pushed substantially in the sliding direction. However, in that case, the operating knob 7 may significantly protrude upward from the mounting groove 6a of the housing, which is not preferable.